Pokey

I'm curious about the process folks choose for preparing a new tire for track use. Hoosier provides instructions for the initial heat cycle of the R7 that includes letting the tires rest for at least 24 hours after for reasons that seem sound, but Avon just describes an initial scrub in consisting of roughly the same process as the Hoosier but without the rest period. I heat cycled my new ZZRs in the first session and set them aside to give them the rest that Hoosier describes but had a tire failure in the next session so put the ZZRs back on. Just curious if it really matters, at least for a tire like the ZZR.

About 10.5" wide. I purchased the large size and then cut into two pieces, one for the carbon guard and the other for the gel coat around the guard.

I used film on the wings and CF guards. Might just be the film I chose, but mine is showing black marking from rubber off of the track. Not noticeable when the backing is the CF, but against the red gel coat of the wings the marks stand out. These rubber "skid" marks rub right off with my fingernail everywhere but the film. Likely not an issue unless you track, and it isn't like it is unsightly, but it might irritate some.

Thanks Bart.

Okay, this isn't really about Group 2 Automotive, but about the polished aluminum and green clamshell Seven sitting in their Woodinville shop right now. Just curious as it doesn't look familiar and I am, of course, interested to learn of any local-to-me owners. Any claimers?

That is a good build blog. The list I compiled as I built is: https://caterham420detailedbuildblog.co.uk/ https://caterham360build.co.uk/ http://caterhamsevenbuild.blogspot.com/ https://www.purplemeanie.co.uk/ https://caterham420rbuild.com/ https://www.caterham7diaries.com/ @mdork, don't hesitate if you want a picture of something assembled. I have a COVID 420R.

Just to tie a bow around this one, I decided on the ZZR. I had also asked Mr. Beachman his thoughts on tires, and with my relative lack of track experience he suggested I stay away from slicks for now. Coincidentally, Caterham emailed the same day Bruce responded letting me know the ZZR were finally in stock so I placed an order before they sold out again.

Similar experience with the track day roll bar, lots of grunting and mumbling to get the holes aligned enough for the bolts to pull things into final alignment.

Looks nice, the proportions of the small light works well.

@Kitcat, the 15" rears are an interesting idea. I wonder if Bruce went that way for the selection of tires available or for gearing - my final gear is 3.91 so the 2" increase in diameter over my 215/55x13 rears might be nice for the track.

@CarlB, thanks for posting this.

@Croc and @SK400, thank you both immensely for all of the info, really got me thinking about other options. I thought 13" wheels would be limiting, but for the track that certainly doesn't seem the case. No decision yet, still waiting on the wheels, but researching further it looks like Hoosier bias slicks will retain the same ride height as the ZZS/ZZR. I find this attractive as switching back and forth won't require suspension changes. Don't suppose anyone has an opinion regarding the Hoosier bias rather than DOT slicks?

@Croc, that is/was/is the idea, a set of ZZS for road and wet, and a set of ZZR for dry track. Caterham only sells the ZZR in the A64, but while looking at the Roger Kraus Racing website I found they also list the A24 compound, hence my questions. Having said that, I had already explored Hoosier R7's rather than the ZZR as they can be sourced easily where the ZZR isn't currently available from Caterham and I'm anticipating RKR not having stock. I should have confirmed rather than assume, but those of you that use the R7 are on 13" wheels, right? The R7 is available in a 205/50x15 which will fit the rear, but I don't see a 15" option for the front. For 13" wheels it looks like the 185/60 in the front and for the rear only the 225/45 will fit the Caterham 8" wheels. The former is slightly taller than the 185/55 ZZS/ZZR, and the latter is slightly wider and a fair amount shorter (0.7" smaller radius).

Thanks @SK400, any idea how the A24 ZZR wears compared to the Hoosier R7?

Thanks Mike. Did you opt for the R7 or did you go with the A7? I had considered and then discounted the R7 on the basis that I couldn't replicate the ZZS dimensions that my car is setup for. Guess if the difference turned out to be material then I could setup around the Hoosier and live with the result on the street with the ZZS. Sounds like I'm talking myself into a decision...

Rather than start a new topic I'll ask here: has anyone tried both ZZR compounds? I'd like to get a set of dedicated track tires and live here in the PNW where temperatures are usually mild and if I encounter a moist day I'll switch to the ZZS. Avon has both the A24 and A64 as a medium-hard compound, but the description seems to indicate the A24 might be for lighter cars which is counterintuitive to me given Caterham exclusively sells the A64 version.

From my limited experience with a relatively new 420R: 1. Odds on you are finding both pedals as it is really easy to do. Happens to me all the time when I mess up my heel-toe technique which is essentially what you are doing on accident. 2. My 420R took a lot of force to get the brakes to bite out of the box. Bedding the pads changed that, they bite now just fine, albeit still take a fair amount of pressure. At this point any improvement would take a different pad compound, but I've no issue locking up the wheels at speed so am happy. 3. I'll defer to those more knowledgable, but will say that if your master cylinder is functional than I would focus my efforts elsewhere. If you haven't bedded your pads I'd start there.

I think this is my favorite thread of all time. Thank you to the entire cast.

Thanks for sharing, looked like great fun!

IMHO, short of dripping wet I don't find plug appearance to be a great way to judge fuel/air for 4 stroke motors. Having said that, if those plugs came out of a 2 stroke I would say yes, lean.

I've been taking notes of your planned engine build and I've got a lot of pictures of CatKong so a little hands-on would turn piracy into collaboration.

Glad to actually have a little info to share back. If there is a future where I replace the current pump, I would go external too for all of the reasons mentioned.

Assuming Caterham is using the same pump consistently, yours will be from an earlier European spec Ford Focus, part number BV61-9H307. My understanding is the ECU controls the pump voltage rather than a mechanical regulator.

I'd take a look at the pins in that connector. I say this from experience - from the factory I had a pin that wasn't properly seated so even though the connection was solid the electrical contact was not.

Have you tried going upstream of the spark plug coils to where they connect to the harness? A loose connection there would account for losing one or more cylinders due to vibration.